fix(idempotency): make kafka-storage command return correct changed_when status

[sverrehu]

Description

This PR sets changed_when for the kafka-storage format command based on the output from the command. This will avoid false positives when nothing is changed.

PS: This is a reimplementation of #1895 for the current development branch. (You implemented part of my original PR in #2181)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Tested in our local provisioning pipeline.

Checklist:

• Any variable/code changes have been validated to be backwards compatible (doesn't break upgrade)
• I have added tests that prove my fix is effective or that my feature works
• If required, I have ensured the changes can be discovered by cp-ansible discovery codebase
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

For local testing of the changed_when logic, you may use the playbook here: https://github.com/sverrehu/ansible-tests/tree/master/kafka-storage-format
You will need to change the binary_base_path in playbook.yml to point to your Kafka command-line installation.

[oc]

lgtm